Apparatus for testing infrared camera

ABSTRACT

An apparatus for testing infrared cameras includes: a front plate which has holes arranged in line, and which is adapted to emit an amount of infrared light; and a back plate which is disposed in parallel to and behind the front plate as viewed from infrared cameras to be tested, and which is adapted to emit a different amount of infrared light when compared with the front plate. The back plate is disposed at lower portions of pillars. On the other hand, the front plate is made vertically movable in front of the back plate and along the pillars. By being controlled by a controller, the front plate is movable from the ground height to a level corresponding to approximately two times the height of the back plate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for testing infraredcameras, which are installed on a vehicle, for measuring distances toobjects.

Priority is claimed on Japanese Patent Application No. 2002-290234,filed Oct. 2, 2002, the content of which is incorporated herein byreference.

2. Description of Related Art

A three-dimensional measuring method has been known in the art in whicha distance to an object is determined using parallax between a pair ofobject images taken by a pair of cameras (stereo cameras). In such amethod, an apparatus for correcting images must be used in order toaccurately measure a distance to an object by correcting shift of imagesdue to distortions of lenses and variations in focal lengths thereof. Inan example of such an apparatus, a specific image pattern, such as aregular grid pattern, for measuring an amount of correction issimultaneously taken in advance using both stereo cameras, and theamounts of corrections in the coordinates are calculated pixel by pixelwith regard to each image taken by each of the cameras. The calculatedresults are stored as a correction table for the coordinates, and thedata stored in an image memory are corrected pixel by pixel using thecorrection table for the coordinates so that accurate image data areobtained. In a method disclosed in, for example, Japanese UnexaminedPatent Application, First Publication No. Hei 11-325889, the correctionsin shifting of images due to distortions of lenses and variations infocal lengths thereof are executed only in the vertical direction.

As an example to which the above-mentioned three-dimensional measuringmethod using stereo cameras is applied, a system is known which detectsobstacles in front of a vehicle earlier than the driver of the vehicledoes, and which notifies the driver of the existence of the obstacles.In this case, in general, infrared cameras, which enable taking infraredimages, are used as the stereo cameras, in order to aid driving underpoor visibility conditions.

As mentioned above, in order to correct shifting of images due todistortions of lenses and variations in focal lengths thereof, aspecific image pattern, such as a regular grid pattern, for measuring anamount of correction is simultaneously taken in advance using bothstereo cameras, and the amounts of corrections in the coordinates arecalculated pixel by pixel with regard to each image taken by each of thecameras; however, in the case of infrared cameras used for the stereocameras, a problem is encountered in that it is difficult to form aregular grid pattern which can be accurately taken by the infraredcameras.

SUMMARY OF THE INVENTION

In view of the above circumstances, an object of the present inventionis to provide an apparatus for testing infrared cameras, which enablesan easy measurement of errors in projected coordinates of objects inboth the horizontal direction and vertical direction.

In order to achieve the above object, the present invention provides anapparatus for testing infrared cameras including: a cover plate whichhas holes arranged in line, and which is adapted to emit an amount ofinfrared light; and an emission source which is disposed in parallel toand behind the cover plate as viewed from infrared cameras to be tested,and which is adapted to emit a different amount of infrared light whencompared with the cover plate.

According to the apparatus for testing infrared cameras configured asdescribed above, by disposing the emission source in parallel to andbehind the cover plate which has holes arranged in line, and by makingthe emission source emit infrared light having an intensity which isgreater than that of the infrared light emitted from the cover plate,infrared light emitting portions aligned in line can be formed using theinfrared light passing through the holes formed in the cover plate. Onthe other hand, by making the emission source emit infrared light havingan intensity which is less than that of the infrared light emitted fromthe cover plate, infrared light non-emitting portions aligned in linecan be formed due to differences between the intensity of the infraredlight emitted from the emission source and the intensity of the infraredlight emitted from a portion of the cover plate other than the holes.

In the apparatus for testing infrared cameras, the emission source mayinclude a metal plate, and a heat source which is connected to the metalplate.

According to the apparatus for testing infrared cameras configured asdescribed above, infrared light can be uniformly emitted from the metalplate by heating the metal plate using the heat source, or by coolingthe metal plate using the heat source. By making the uniformly emittedinfrared light pass through the holes formed in the cover plate, theinfrared light emitting portions which are accurately aligned or theinfrared light non-emitting portions which are accurately aligned can beeasily formed due to difference between the intensity of the infraredlight emitted from the emission source and the intensity of the infraredlight emitted from the cover plate.

In the apparatus for testing infrared cameras, the emission source maycomprises a metal plate, and an element which is adhered to the metalplate, and which has an infrared emissivity that is higher than that ofthe cover plate.

According to the apparatus for testing infrared cameras configured asdescribed above, because the element having an infrared emissivity thatis higher than that of the cover plate is adhered to the metal plate,the infrared light emitting portions which are accurately aligned can beformed at low cost by making the element uniformly emit infrared light,and by making the infrared light pass through the holes formed in thecover plate.

In the apparatus for testing infrared cameras, the cover plate may havebeen subjected to a processing for reducing infrared light reflection.

According to the apparatus for testing infrared cameras configured asdescribed above, because the cover plate has been subjected to aprocessing for reducing infrared light reflection, the infrared lightemitted from the emission source can be prevented from being reflectedby a vehicle on which the infrared cameras to be tested are installed,and also, reflected infrared light can be prevented from being reflectedby the cover plate.

In the apparatus for testing infrared cameras, the cover plate may bevertically movable in front of the emission source as viewed from theinfrared cameras to be tested from a first position at which testing ofthe infrared cameras is executed to a second position which is higherthan the first position. The second position may be preferably set to besufficiently higher than the first position so that the cover plate isnot heated by a heat source of the emission source.

According to the apparatus for testing infrared cameras configured asdescribed above, the vertical level of the cover plate can be adjustedin accordance with the vertical levels of the infrared cameras to betested even when the vertical levels of the infrared cameras arechanged. In addition, by moving the cover plate from a position in frontof the emission source so as to make the distance between the coverplate and the emission source greater, the cover plate is prevented frombeing heated unnecessarily, which leads to emission of unnecessaryinfrared light, or the cover plate is prevented from being cooledunnecessarily, which leads to non-emission of necessary infrared light.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an embodiment of an apparatus fortesting infrared cameras according to the present invention.

FIG. 2 is a plan view showing a target portion of the apparatus fortesting infrared cameras according to the above embodiment.

FIG. 3 is a front view showing the target portion of the apparatus fortesting infrared cameras according to the above embodiment.

FIG. 4 is a diagram showing a grayscale image of the target portion ofthe apparatus for testing infrared cameras according to the aboveembodiment taken by infrared cameras installed on a vehicle.

FIG. 5 is a diagram showing a binarized image obtained by applying abinarization process to the grayscale image of the target portion.

FIG. 6 is a flowchart showing a process for testing infrared cameras, inwhich the apparatus for testing infrared cameras according to the aboveembodiment and an image processing unit installed in the vehicle areused.

FIG. 7 is a diagram showing a property curve of error in coordinatesprojected onto an image plane, which was obtained using the apparatusfor testing infrared cameras according to the above embodiment.

FIG. 8A is a schematic diagram illustrating the relationship between adistance R from the center of a lens to an object and the coordinates ofthe geometric center of the object, and FIG. 8B is a diagram showing theproperty curve of error in coordinates projected onto an image plane,which was obtained using the apparatus for testing infrared camerasaccording to the above embodiment, as a property curve of error incoordinates with respect to the distance R.

FIG. 9 is a schematic diagram illustrating mounting angle (panning angleθ) of an infrared camera installed on a vehicle.

FIG. 10 is a diagram showing a grayscale image of the target portion ofthe apparatus for testing infrared cameras according to the aboveembodiment taken by the infrared cameras installed on the vehicle.

FIG. 11 is a diagram showing another property curve of error incoordinates projected onto an image plane, which was obtained using theapparatus for testing infrared cameras according to the above embodimentin an alternative process.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention will be explained below withreference to appended drawings.

FIG. 1 is a perspective view showing an embodiment of an apparatus fortesting infrared cameras according to the present invention, which is tobe installed in a manufacturing line in a plant. FIG. 2 is a plan viewshowing a target portion of the apparatus for testing infrared camerasaccording to the present embodiment. FIG. 3 is a front view showing thetarget portion of the apparatus for testing infrared cameras.

As shown in FIG. 1, the apparatus for testing infrared cameras accordingto the present embodiment includes a back plate 2 and a front plate 3which together form a target portion that is disposed in front of avehicle 1 which is provided with infrared cameras to be tested at thefront end thereof. The back plate 2, formed of an aluminum plate, actsas an infrared light emission source when the entirety thereof is heatedor cooled. The front plate 3, also formed of an aluminum plate, isdisposed closer to the vehicle 1 than the back plate 2. Circular throughholes (identified as H1-H11 in FIG. 3, hereinafter referred to as targetholes) having the same size with respect to each other are formed in thefront plate 3 at regular intervals. As shown by the dotted lines in FIG.2, the target holes H1-H11 extend all of the way through the front plate3.

The back plate 2 is a plate-shaped element whose width in the horizontaldirection is approximately the same as that of the vehicle 1, and whoseheight in the vertical direction is sufficiently large when comparedwith the vehicle 1 regardless of models of the vehicle 1 so that testingof the infrared cameras is allowed wherever the infrared cameras areinstalled on the vehicle 1. The back plate 2 is disposed at lowerportions of pillars 4 a and 4 b. On the other hand, the front plate 3 ismade vertically movable in front of the back plate 2 and along thepillars 4 a and 4 b. By being controlled by the controller 5, the frontplate 3 is movable from the ground height to a level corresponding toapproximately two times the height of the back plate 2. Accordingly, thevertical level of the target portion including the back plate 2 and thefront plate 3 can be adjusted to a level of the infrared cameras evenwhen the level of the infrared cameras are changed depending on themodels of the vehicle 1.

The back plate 2 and the front plate 3 will be further explained belowin detail. As shown in FIG. 2, the back plate 2 is provided withtemperature adjusting devices 6 such as heaters or Peltier elements onthe backside thereof as viewed from the vehicle 1 in order to executeheating or cooling of the entirety of the back plate 2.

The direct transmission of heat from the back plate 2 to the front plate3 is prevented by supporting the front plate 3 by the pillars 4 a and 4b so that the front plate 3 is separated from the back plate 2 by anappropriate distance, and by fabricating the pillars 4 a and 4 b with amaterial having low thermal conductivity. When the front plate 3 ismoved to the uppermost portions of the pillars 4 a and 4 b, the frontplate 3 is not affected by heating and cooling of the back plate 2.

As shown in FIG. 3, the front plate 3 has the circular target holes(eleven target holes H1 to H11 in this embodiment) which are arranged inline in the horizontal direction along the center line of the frontplate 3 at a regular interval; therefore, the back plate 2 can be seenfrom the vehicle 1 through the target holes H1 to H11. In addition,raised paper 3 a having low reflectance is adhered to the front face(front surface) of the front plate 3 as viewed from the vehicle so thatthe infrared light reflected by the vehicle 1 or emitted from thevehicle 1 will not be reflected by the front plate 3 and will not returnto the vehicle 1.

In the target portion as configured above, the back plate 2 and thefront plate 3 are overlaid each other, and the back plate 2 is heated.The infrared light emitted from the back plate 2 is taken by theinfrared cameras installed on the vehicle 1 through the target holes H1to H11 formed in the front plate 3 to obtain a grayscale image shown inFIG. 4. A binarization process is applied to the grayscale image shownin FIG. 4 to obtain a binarized image shown in FIG. 5.

In contrast, when the back plate 2 is cooled, the infrared light emittedfrom the front plate is take by the infrared cameras; therefore, anotherbinarized image is obtained which is reversed in white and black whencompared with the binarized image shown in FIG. 4.

In a state in which the back plate 2 is heated to make the back plate 2emit infrared light, infrared light having higher intensity can beobtained by adhering a material having an infrared reflectance greaterthan 0.9 such as paper or carbon to the back plate 2. Accordingly, wheninfrared light having higher intensity is desired, the back plate 2 isheated using the temperature adjusting devices 6 in addition to adheringpaper or carbon to the back plate 2. When low cost is desired for theapparatus for testing infrared cameras, the temperature adjustingdevices 6 may be omitted, and just the back plate 2 having paper orcarbon thereon may be used as the infrared light emission source.

Next, a verification process for the on-vehicle infrared cameras usingthe apparatus for testing infrared cameras of the present embodimentwill be explained below.

FIG. 6 is a flowchart showing the verification process for the infraredcameras, in which the apparatus for testing infrared cameras accordingto the above embodiment and an image processing unit installed in thevehicle 1 are used.

In FIG. 6, the image processing unit obtains infrared images as anoutput signal of the stereo infrared cameras (step S1), executes an A/Dconversion (step S2), and stores grayscale images in an image memory(step S3). A right image of the target holes H1 to H11 is obtained by aright infrared camera, and a left image of the target holes H1 to H11 isobtained by a left infrared camera.

In step S3, the grayscale images such as shown in FIG. 4 is obtained,and then a binarization process is applied to each of the right and leftimages to obtain the binarized images such as shown in FIG. 5 (step S4).In the binarization process, regions in the image that are brighter thana brightness threshold ITH are deemed as “1” (i.e., white), and regionsin the image that are darker than the brightness threshold ITH aredeemed as “0” (i.e., black).

Next, the geometric center of each of the target holes H1 to H11 in thebinarized image is calculated (step S5).

Next, an error in projected coordinates are calculated (step S6) basedon the differences between the theoretical projected X coordinates andthe observed X coordinates of the geometric centers obtained in step S5.More specifically, the coordinates of the target holes H1 to H11 inactual space projected onto the image (the theoretical projected Xcoordinates) are obtained using Equation (1) shown below. The errors inprojected X coordinates are obtained by subtracting the observed Xcoordinates of the geometric centers from the theoretical projected Xcoordinates.x=(F·X)/(p·Z)  Equation (1)

In Equation (1), “x” indicates the coordinate of the target holeprojected onto the image, “X” indicates position of the target hole inthe actual space shown in FIG. 4, “Z” indicates the distance between thetarget hole in the actual space and the camera, “p” indicates pitch ofpixels, and “F” indicates the focal length of the lens of the camera.

Moreover, with regard to each position of the binarized target holes H1to H11 shown in FIG. 5, an error in projected X coordinate iscalculated, and then a property curve of error in coordinates projectedonto the image plane for the errors in projected X coordinates of thetarget holes H1 to H11 is obtained with regard to each of the right andleft images (step S7). More specifically, as shown in FIG. 7, theproperty curve of error in the coordinates projected onto the imageplane, which corresponds to the errors in projected X coordinates of thetarget holes H1 to H11, is drawn by plotting points in such a mannerthat the observed X coordinates of the geometric centers are measuredalong the x-axis, and the errors in projected X coordinates are measuredalong the y-axis, and by curve-fitting the plotted points using a lineor using a polynomial approximation. Equation (2) shown below is appliedto a six-degree polynomial approximation for the property curve of errorin the coordinates projected onto the image plane as shown in FIG. 7.The “α” shown in FIG. 7, for example, indicates the error in theprojected coordinate of the target hole H9.y=a·x ⁶ +b·x ⁵ +c·x ⁴ +d·x ³ +e·x ² +f·x+g  Equation (2)The obtained property curve of error in the coordinates projected ontothe image plane is stored as a camera coordinates correction parameter(step S8).

The property curve of error in the coordinates projected onto the imageplane shown in FIG. 7 indicates the errors in the projected X coordinatewith respect to the observed X coordinates of the geometric centers ofthe objects (target holes); however, another property curve of error inthe coordinates projected onto the image plane, which indicates theerrors in the projected coordinate with respect to the distance from thecenter of the lens of the camera, may be drawn and used becausedistortion in a lens is, in general, symmetrical about the center of thelens. More specifically, when the observed coordinates of the geometriccenter of an object is expressed by “(Xp, Yp)” as shown in FIG. 8A, andthe distances R from the center of the lens calculated using Equation(3) are measured along the x-axis instead of the observed X coordinatesof the geometric centers in the case of FIG. 7, the errors in theprojected coordinate with respect to the distances R from the center ofthe lens are indicated as shown in FIG. 8B.R=(Xp ² +Yp ²)^(1/2)  Equation (3)

In the above method for obtaining the property curve of error in thecoordinates projected onto the image plane based on the differencesbetween the theoretical projected X coordinates and the observed Xcoordinates of the geometric centers, the position and angle of thecamera must be adjusted so that the center target hole H6, which is tobe the basis of measurement, is positioned at the center of the image inorder to use Equation (1); however, it is difficult to accurately adjustthe position and angle of the camera due to limitations in accuracy ofinstallation of the cameras at a factory, due to limitations in accuracyof equipment in the factory.

However, even when the position and angle of the camera are notadjusted, the theoretical projected coordinates can be calculated if aninstallation angle (i.e., a panning angle) θ of the camera, which isillustrated in FIG. 9, can be found. In this case, the coordinatesprojected onto the image plane (i.e., the theoretical projected Xcoordinates) of the target holes H1 to H11 are calculated based on thepositions of the target holes H1 to H11 in the actual space usingEquation (4).X={F·(X·cos θ+Z·sin θ)}/{p·(−X·sin θ+Z·cos θ)}  Equation (4)

In Equation (4), “x” indicates the coordinate of the target holeprojected onto the image, “X” indicates position of the target hole inthe actual space shown in FIG. 4, “Z” indicates the distance between thetarget hole in the actual space and the camera, “p” indicates pitch ofpixels, “F” indicates the focal length of the lens of the camera, and“θ” indicates the panning angle of the camera.

Next, another method for obtaining the property curve of error in thecoordinates projected onto the image plane using the apparatus fortesting infrared cameras according to the present embodiment will beexplained.

In another method for obtaining the property curve of error in thecoordinates projected onto the image plane, the property curve of errorin the coordinates projected onto the image plane is obtained based onthe differences between the observed distances and the theoreticaldistances from the center target hole H6, as the basis of measurement,to the other target holes.

More specifically, in step S3 shown in FIG. 6, grayscale images areobtained, and then a binarization process is applied to each of theright and left images to obtain the binarized images. In thebinarization process, regions in the image that are brighter than abrightness threshold ITH are deemed as “1” (i.e., white), and regions inthe image that are darker than the brightness threshold ITH are deemedas “0” (i.e., black).

Next, the geometric center of each of the target holes H1 to H11 in thebinarized image is calculated.

As shown in FIG. 10, the distances on the image from the center targethole H6 to the other target holes (i.e., theoretical distances LR1 toLR11) are calculated using Equation (5). Next, the errors in projected Xcoordinates (the errors in projected X coordinates=the observeddistances from the center target hole H6 to the other target holes—thetheoretical distances from the center target hole H6 to the other targetholes) are obtained based on the observed distances from the centertarget hole H6 to the other target holes (LJ1 to LJ11) and thetheoretical distances from the center target hole H6 to the other targetholes (LR1 to LR11).1=(F·L)/(p·Z)  Equation (5)

In Equation (5), “1” indicates the distances on the image from thecenter target hole H6 to the other target holes, “L” indicates thedistances in the actual space from the center target hole H6 to theother target holes as shown in FIG. 10, “Z” indicates the distances inthe actual space from the target holes to the camera, “p” indicatespitch of pixels, and “F” indicates the focal length of the lens of thecamera.

Moreover, with regard to each position of the binarized target holes H1to H11 shown in FIG. 5, the error in the projected X coordinate iscalculated as shown in TABLE 1, and then a property curve of error inthe coordinates projected onto the image plane is obtained based on theerrors in the projected X coordinates of the target holes H1 to H11.More specifically, as shown in FIG. 11, the property curve of error inthe coordinates projected onto the image plane, which corresponds to theerrors in projected X coordinates of the target holes H1 to H11, isdrawn by plotting points in such a manner that the observed Xcoordinates of the geometric centers (i.e., the observed distances fromthe target hole H6 and to the other target holes) are measured along thex-axis, and the errors in projected X coordinates are measured along they-axis, and by curve-fitting the plotted points using a line or using apolynomial approximation. Equation (2) shown above is applied to asix-degree polynomial approximation for the property curve of error inthe coordinates projected onto the image plane as shown in FIG. 11. The“β” shown in FIG. 11, for example, indicates the error in the projectedX coordinate (i.e., (LJ9-LR9)) corresponding to the distance from thecenter target hole H6 to the target hole H9.

TABLE 1 Observed distance Theoretical distance from H6 to each of fromH6 to each of Error in the the other target the other target projected XTarget hole holes holes coordinate H1 LJ1 LR1 LJ1–LR1 H2 LJ2 LR2 LJ2–LR2H3 LJ3 LR3 LJ3–LR3 H4 LJ4 LR4 LJ4–LR4 H5 LJ5 LR5 LJ5–LR5 H6 — — — H7 LJ7LR7 LJ7–LR7 H8 LJ8 LR8 LJ8–LR8 H9 LJ9 LR9 LJ9–LR9 H10 LJ10 LR10LJ10–LR10 H11 LJ11 LR11 LJ11–LR11

In the method for obtaining the property curve of error in thecoordinates projected onto the image plane based on the differencesbetween the observed distances and the theoretical distances from thecenter target hole H6, as the basis of measurement, to the other targetholes, even when there is a panning angle θ of the cameras, the propertycurve of error in the coordinates projected onto the image plane can beaccurately obtained based on the differences between the observeddistances and the theoretical distances from the center target hole H6to the other target holes because the distances from the center targethole H6 to the other target holes will not change with the panning angleθ.

As explained above, the apparatus for testing infrared cameras accordingto the present embodiment includes the front plate 3 having the holesarranged in line, and the back plate 2, as the infrared light emissionsource, disposed behind the front plate 3 while being in parallel withthe front plate 3. In the apparatus for testing infrared cameras, byheating the back plate 2 using the temperature adjusting device 6 sothat the back plate 2 emits infrared light having an intensity which isgreater than that of the infrared light emitted from the front plate 3,the infrared light emitting portions aligned in line can be formed usingthe infrared light passing through the holes formed in the front plate3. In contrast, when the back plate 2 is cooled using the temperatureadjusting device 6, because the front plate 3 emits infrared lighthaving an intensity which is greater than that of the infrared lightemitted from the back plate 2, white and black in the image taken by theinfrared camera are reversed.

Moreover, if the front plate 3 has been subjected to a processing forreducing infrared light reflection, the infrared light, which is emittedfrom the back plate 2, and is then reflected by the vehicle 1 on whichthe infrared cameras to be tested are installed, can be prevented frombeing reflected by the front plate 3, and thus effects of the reflectedinfrared light in the test of the infrared cameras can be eliminated.

Furthermore, by adhering an element having a high infrared emissivitysuch as paper or carbon to the back plate 2 so that the element emitsinfrared light having an intensity which is greater than that of theinfrared light emitted from the front plate 3, the cost of the apparatusfor testing infrared cameras can be reduced because the temperatureadjusting device 6 for heating the back plate 2 may be omitted.

In addition, by making the front plate 3 vertically movable in front ofthe back plate 2, the vertical level of the front plate 3 can beadjusted in accordance with the vertical levels of the infrared cameraseven when the vertical levels of the infrared cameras are changed due tochange in the model of the vehicle 1. Moreover, by moving the frontplate 3 from a position in front of the back plate 2 so as to make thedistance between the front plate 3 and the back plate 2, the front plate3 is prevented from being heated unnecessarily, which leads to emissionof unnecessary infrared light, or the front plate 3 is prevented frombeing cooled unnecessarily, which leads to non-emission of necessaryinfrared light.

Accordingly, the distortions of the lenses in various directions andvariations in the focal lengths of the lenses used in the infraredcameras to be tested can be confirmed as the property curve of error inthe coordinates projected onto the image plane by taking the images ofthe infrared emitting portions uniformly formed using the apparatus fortesting infrared cameras, and by comparing the positions of the infraredemitting portions in the actual space with the coordinates of theinfrared emitting portions projected onto the image plane.

Advantageous Effects of the Invention

As explained above, according to the apparatus for testing infraredcameras of the present invention, by disposing the emission source inparallel to and behind the cover plate which has holes arranged in line,and by making the emission source emit infrared light having anintensity which is greater than that of the infrared light emitted fromthe cover plate, infrared light emitting portions aligned in line can beformed using the infrared light passing through the holes formed in thecover plate. On the other hand, by making the emission source emitinfrared light having an intensity which is less than that of theinfrared light emitted from the cover plate, infrared light non-emittingportions aligned in line can be formed due to difference between theintensity of the infrared light emitted from the emission source and theintensity of the infrared light emitted from a portion of the coverplate other than the holes.

Therefore, the testing of the infrared cameras can be accuratelyperformed using the infrared light emitting portions which are clearlydelimited, or using the infrared light non-emitting portions which aretaken by the infrared cameras as a reversed pattern when compared withthe infrared light emitting portions.

According to another apparatus for testing infrared cameras of thepresent invention, the infrared light emitting portions which areaccurately aligned or the infrared light non-emitting portions which areaccurately aligned can be easily formed by heating the metal plate usingthe heat source, or by cooling the metal plate using the heat source sothat infrared light is uniformly emitted from the metal plate.

Therefore, by controlling the heat source, the contrast in the image ofthe emission source taken by the infrared cameras can be increased, andthe testing of the infrared cameras can be accurately performed.

According to another apparatus for testing infrared cameras of thepresent invention, because the element having an infrared emissivitythat is higher than that of the cover plate is adhered to the metalplate, the infrared light emitting portions which are accurately alignedcan be formed at low cost by making the element uniformly emit infraredlight.

Therefore, the cost of the apparatus for testing infrared cameras can bereduced.

According to another apparatus for testing infrared cameras of thepresent invention, because the cover plate has been subjected to aprocessing for reducing infrared light reflection, the infrared lightemitted from the emission source can be prevented from being reflectedby a vehicle on which the infrared cameras to be tested are installed,and also reflected infrared light can be prevented from being reflectedby the cover plate.

Therefore, distortions in the infrared light emitting portions or in theinfrared light non-emitting portions due to the infrared light reflectedby the vehicle and reflected by the cover plate can be prevented, andthe testing of the infrared cameras can be accurately performed.

According to another apparatus for testing infrared cameras of thepresent invention, the vertical level of the cover plate can be adjustedin accordance with the vertical levels of the infrared cameras to betested. In addition, by moving the cover plate from a position in frontof the emission source, the cover plate is prevented from being heatedunnecessarily, which leads to emission of unnecessary infrared light, orthe cover plate is prevented from being cooled unnecessarily, whichleads to non-emission of necessary infrared light.

Therefore, in a manufacturing line of automobiles, for example, thevertical level of the cover plate can be adjusted to the level of theinfrared cameras to be tested depending on the models of the vehicle.The cover plate is disposed in front of the emission source only whenthe cover plate is required in the testing of the infrared cameras whichis not continuously performed so that the infrared light emittingportions which are accurately aligned or the infrared light non-emittingportions which are accurately aligned are formed, and thus the testingof the infrared cameras can be accurately performed at any time.

While preferred embodiments of the invention have been described andillustrated above, it should be understood that these are exemplary ofthe invention and are not to be considered as limiting. Additions,omissions, substitutions, and other modifications can be made withoutdeparting from the spirit or scope of the present invention.Accordingly, the invention is not to be considered as being limited bythe foregoing description, and is only limited by the scope of theappended claims.

1. An apparatus for testing infrared cameras, comprising: a cover platewhich has a plurality of holes formed therethrough and arranged in line,said cover plate adapted to emit an amount of infrared light; a pair ofspaced-apart support pillars formed from a material having low thermalconductivity, the cover plate being operatively attached to the supportpillars so as to be vertically adjustable thereon; and an emissionsource which is operatively attached to the support pillars and disposedin parallel to and behind the cover plate as viewed from infraredcameras to be tested, and which is adapted to emit a different amount ofinfrared light when compared with the cover plate, the emission sourcecomprising a metal plate, and an element which is adhered to the metalplate, and which has an infrared emissivity that is different from thatof the cover plate.
 2. An apparatus for testing infrared cameras,according to claim 1, wherein the emission source comprises a heatsource which is connected to the metal plate.
 3. An apparatus fortesting infrared cameras, comprising: a cover plate which has holesarranged in line, and which is adapted to emit an amount of infraredlight; and an emission source which is disposed in parallel to andbehind the cover plate as viewed from infrared cameras to be tested, andwhich is adapted to emit a different amount of infrared light whencompared with the cover plate, wherein the emission source comprises ametal plate, and an element which is adhered to the metal plate, andwhich has an infrared emissivity that is higher than that of the coverplate.
 4. An apparatus for testing infrared cameras, according to claim1, wherein the cover plate has been subjected to a processing forreducing infrared reflection.
 5. An apparatus for testing infraredcameras, comprising: a cover plate which has holes arranged in line, andwhich is adapted to emit an amount of infrared light; and an emissionsource which is disposed in parallel to and behind the cover plate asviewed from infrared cameras to be tested, and which is adapted to emita different amount of infrared light when compared with the cover plate;wherein the cover plate is vertically movable in front of the emissionsource as viewed from the infrared cameras to be tested from a firstposition at which testing of the infrared cameras is executed to asecond position which is higher than the first position.
 6. An apparatusfor testing infrared cameras, according to claim 5, wherein the secondposition is sufficiently higher than the first position such that thecover plate is not heated by a heat source of the emission source.
 7. Anapparatus for testing infrared cameras according to claim 1, wherein theemission source comprises a heating and cooling source which isconnected to the metal plate.
 8. An apparatus for testing infraredcameras according to claim 3, wherein said metal plate is aluminum. 9.An apparatus for testing infrared cameras according to claim 1, whereinpaper is adhered to a front of said cover plate to reduce infraredreflection therefrom.
 10. An apparatus for testing infrared camerasaccording to claim 3, further including pillars along which at least oneof the metal plate and cover plate are vertically movable.
 11. Anapparatus for testing infrared cameras according to claim 10, whereinboth said metal plate and cover plate are vertically movable along saidpillars.
 12. An apparatus for testing infrared cameras according toclaim 10, wherein said pillars are formed of a material having lowthermal conductivity.